Champix side effects

As many as two-thirds of smokers in the UK want to quit. Prescription medications like Champix (Varenicline) can triple your chance of quitting successfully. Champix (Varenicline) reduces cravings and nicotine withdrawal symptoms by blocking the nicotine receptors in your brain making smoking less pleasurable and by triggering the release of dopamine.

It's one of only two nicotine-free medications for quitting smoking that is FDA approved, which means the cigarettes aren't replaced with something else.

Champix is taken for an initial course of 12 weeks. This can be extended for a further 12 weeks, to further reduce the risk of a relapse. But, as with any medication, it's important to understand how it works, its advantages and its potential side effects.

Known side effects

The following are the known side effects associated with taking varenicline (Champix) based on data from drug trials of approximately 5,000 patients, according to the electronic Medicines Compendium (eMC). They are classified in the table below as:

Very common – affecting more than 1 in 10 users

Common – affecting between 1 in 10 and 1 in 100 users

Uncommon – affecting between 1 in 100 and 1 in 1,000 users

Rare – affecting between 1 in 1,000 and 1 in 10,000 users

Common side effects

Uncommon side effects

Rare side effects

Common cold

Abnormal dreams

Insomnia

Headache

Nausea

Bronchitis

Sinusitis

Increase or decrease of appetite

Rash

Pruritus (Itching)

Joint pain

Muscle pain

Fatigue

Fungal infection

Viral infection

Panic attacks

Abnormal thoughts

Restlessness

Mood swings

Depression and anxiety

Hallucinations

Sensitivity to touch (hypoaesthesia)

Tinnitus (ringing in ears)

Angina pectoris (chest pain)

Tachycardia, palpitations or increased heart rate

Increased blood pressure

Hot flushes

Respiratory tract inflammation or congestion

Dysphonia or throat infection

Sinus congestions and hay fever

Haematochezia (blood in stool) or change in bowel habits

Gastritis

Eructation (burping)

Mouth ulcers or gingival pain

Frequent urination during day or night

Influenza symptoms

Abnormal liver function

Decrease in platelet count

Excessive thirst (Polydipsia)

Dysphoria

Stroke or cerebrovascular accident

Increased tonicity (hypertonia)

Reduced taste (hypogeusia)

Circadian rhythm sleep disorder

Partial vision loss (scotoma)

Sclera discolouration at side of pupils

Mydriasis (dilation of pupil)

Photophobia or light sensitivity

Myopia or short sightedness

Atrial fibrillation or ECG changes

Laryngeal pain

Snoring

Haematemesis (vomiting of blood)

Abnormal faeces

Coated tongue

Joint stiffness

Chest inflammation (costochondritis)

Increased volume of urine (polyuria) of sugar in urine (glycosuria)

Vaginal discharge

Sexual dysfunction

Abnormal semen analysis

Increase in C-reactive protein

Decrease in blood calcium

Other side effects and risks

here have been reports of other rare side effects and risks with Champix. The level of these or exact links are not yet fully known.

Champix and mental health

There also may be a connection between Champix and other mental health conditions – with potential side effects of depression, hostility or suicidal thoughts and behaviours. There have been a number of studies carried out, but results have varied. One study found that the likelihood of Champix being linked to suicidal thoughts and depression was eight times higher than that of nicotine replacement products. Other studies found statistically significant link or increased risk from the drug.

While Champix is a highly effective treatment, the FDA did request that it include a black box warning in 2009, to warn of this potential link. Pfizer, the manufacturer of Champix, are conducting their own large scale study to look at the link, and their more definitive results are expected to be available in 2017.

Champix and heart problems

A study of 700 smokers with existing cardiovascular disease looked at the results of treating patients with Champix versus a placebo. They found a slight increase in the number of people who experienced heart attacks for those treated with Champix over a placebo. Whilst these results were not statistically significant and could be random, the FDA posted a warning in 2011 to notify people that there was a chance of increasing their likelihood of cardiovascular complications.

How to prevent the risk of side effects

Overall, your chance of experiencing serious side effects from taking Champix is low. Across 17 studies, only 3.2% of participants taking Champix reported developing any serious health problems, compared with 2.4% of participants not taking it.

However, if you have certain other risk factors, Champix may not suitable for you. It's not advised to take Champix if you've ever suffered from:

Depression or mental health conditions

Kidney disease

Heart disease or circulation problems

Heavy alcohol use

Dealing with Champix side effects

Nausea is the most common side effect you are likely to experience. It affects 3 in 10 people taking Champix but this can be eased by taking your tablet with food or by speaking to your doctor about decreasing your dosage.

It's recommended that if you experience any change in mood or behaviour while taking Champix, you should stop taking it immediately as a precaution and should contact your doctor. If you experience any other signs of serious side effects or have any symptoms that are concerning you, you are advised to speak to your doctor or pharmacist.

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